Chapter 2: Molecules of Life - Vocabulary Flashcards

Vocabulary flashcards covering chemical bonds, properties of water, pH and buffers, organic chemistry, carbon structures, and functional groups from Chapter 2.

Hydrogen bond

A weak attraction between a hydrogen atom bonded to a highly electronegative atom and another electronegative atom.

Van der Waals interactions

Weak, short-range attractive forces between molecules or atoms.

Hydrophilic

Water-loving molecules, typically ionic or polar, that dissolve readily in water.

Hydrophobic

Water-hating molecules, typically nonpolar, that are insoluble in water.

Polar molecules

Molecules containing regions of positive and negative charge.

Solvent

The dissolving agent of a solution, such as water.

Solute

The substance that is dissolved in a solution, such as salt.

Solution

A liquid that is a homogenous mixture of two or more substances.

Hydrophobic effect

The phenomenon that occurs when polar molecules exclude nonpolar ones, which is important in cell membrane formation and protein folding.

Cohesion

The property where hydrogen bonds cause water molecules to stay close to each other.

pH

A measure of hydrogen ion concentration in an aqueous solution, defined mathematically as $pH = -\text{log}[H^+]$.

Buffers

Solutions containing a weak acid and its corresponding base that combine reversibly with $H^+$ ions to minimize changes in $[H^+]$ and $[OH^-]$.

Organic chemistry

The chemistry of carbon-containing compounds.

Organic molecules

Molecules containing carbon, which serve as life's chemical backbone.

Isomers

Molecules that have the same chemical formula but different structural arrangements, which can lead to different properties and functions.

Functional Groups

Groups of one or more atoms that possess a particular chemical property on their own.

Amino group

A polar functional group with formula $-NH_2$ that is positively charged at the pH of a cell, behaves as a base, and is hydrophilic.

Amide group

A polar, hydrophilic functional group with the formula $-C(=O)NH-$.

Carboxyl group

A polar functional group with formula $-COOH$ that is negatively charged at the pH of a cell, behaves as an acid, and is hydrophilic.

Carbonyl group

A polar, hydrophilic functional group with the formula $>C=O$.

Hydroxyl group

A polar, hydrophilic functional group with the formula $-OH$.

Sulfhydryl group

A polar functional group with the formula $-SH$ that forms $S-S$ disulfide bonds.

Methyl group

A nonpolar functional group with the chemical formula $-CH_3$.

Phosphate group

A polar functional group with formula $-OPO_3H_2$ that is negatively charged at the pH of a cell and is hydrophilic.